1) Button-down 2) Calm 3) Composed 4) Conservative 5) Conservative in style 6) Decorous 7) Demure 8) Dignified 9) Dully sedate 10) Far from flighty 11) Far from frivolous 12) Far from frolicsome 13) Far from wacky 14) Grave 15) Hardly capricious 16) Hardly flighty 17) Hardly manic 18) Laid-back 19) No-nonsense Found on https://www.crosswordclues.com/clue/staid
Staid adjective [ From Stay to stop.] Sober; grave; steady; sedate; composed; regular; not wild, volatile, or fanciful. 'Sober and staid persons.' Addison. « O'erlaid with black, staid Wisdom's hue.» Milton. Syn. -- Sober; grave; steady; steadfas... Found on http://www.encyclo.co.uk/webster/S/181